Gmail app not letting me add accountsSupport

I can't add another Gmail account to the Gmail app. It keeps timing out saying "Can't establish a reliable data connection to the server."
I searched Google and tried to log into the Youtube app so it would add the account to my list, but it didn't.
I don't want to even try a hard reset, because it "might" work.
Anyone find a solution to this problem? Looking around the Net, I see I'm not the only person to have this issue.